Devices using a flexible chain, belt, or other transporting surface guided along a conveyor path for moving articles from one point to another are known in the art. A conveyor path is typically laid out or defined by structural members, such as girders establishing a raceway formed along their length for supporting a chain. Drive units, such as a sprocket drive, are disposed along the path for engaging teeth formed in said chain to move said chain along said path. Articles to be conveyed sit on this chain, which may also have cleats or other suitable structure for gripping or catching the articles to be conveyed.
The chain is typically composed of a series of chain links suitable, joined together to form a looped or endless conveying surface that is flexible or articulated to be capable of passing through both vertical and horizontal curves. An example of such a chain is shown in Lachonius, et al. U.S. Pat. No. 4,597,492.
Lachonius U.S. Pat. No. 4,511,031 shows a conveyor said to be comprised of easily mountable girder sections. A conveyor chain 1 is driven and guided in an open track on girder 2. Girder 2 is symmetrical about a horizontal plane, whereby belt 1 returns on the opposite or under side of the girder 2. Strips of plastic material (see U.K. Patent Application No. 2,172,870A) provide bearing surfaces along which the belt moves. Two or more girders may be interconnected.
A problem with the Lachonius device is that the belt 1 is fixedly retained in the track by supporting members or ears formed in the girders that extend inwardly from both sides of the open track to retain said chain. This is necessary because the chain must be restrained against gravity in the return raceway on the bottom track of the girder or in vertical and horizontal curves. Accordingly, if the chain needs to be removed for repair, replacement, or cleaning, either the end of the conveyor path must be available or the entire girder structure broken apart, and the chain must somehow be broken or separated at one point in the endless loop and pulled out sufficiently to reach the trouble spot. When the chain is to be reinserted, it must be laboriously threaded back in. Because conveyor systems can easily reach several hundred feet in length, such a procedure can be awkward, time consuming, and costly.